1. Field of the Invention
The present invention is related with a control information recording method and apparatus for recording in advance, onto an information record medium of WO (Write Once) type (hereafter, referred to as a DVD-R (Digital Video or Versatile Disk-Recordable)) among information record media whose recording densities are dramatically improved over conventional CDs (Compact Disks) and the like represented by the DVD, control information such as address information, a synchronization information etc. (hereafter, referred to as xe2x80x9cpre-informationxe2x80x9d) required to record and reproduce the substantial record information such as video information and audio information to and from the DVD-R. The present invention is also related with an information recording method and apparatus for recording the record information onto the DVD-R while reproducing the pre-information from the DVD-R on which the pre-information has been already recorded.
2. Description of the Related Art
In an information record medium such as a WO type postscript optical disk and the like, the pre-information for a position retrieval at a time of writing the record information is recorded in advance onto the information record medium at a pre-format stage in manufacturing the information record medium. As a method of pre-formatting this pre-information, an information record track (a groove track or a land track) for recording the record information is wobbled in a form of a wave so as to record the pre-information. Alternatively, a pre-pit is formed on a portion different from a portion where the record information is recorded on the information record track, so as to record the pre-information.
However, in a case of the pre-format of the pre-information by the wobbling, the information record track itself is swung to the right and left relative to a rotation direction of the information record medium on the basis of a wobbling signal. This results in a problem that a C/N ratio (Carrier to Noise ratio) is poor because of a restriction in a modulation degree of the wobbling signal (wobbling amplitude) due to a relation to an adjacent information record track. Further, considering an interference resulting from the adjacent information record track since the adjacent information record tracks are close to each other by the wobbling, it is difficult to make a trackpitch narrow. This results in a problem of limitation in improvement of the recording density.
On the other hand, in a case of the pre-format of the pre-information by the pre-pit, since the pre-pit is formed on the information record track, the recordable amount of the substantial record information is reduced by the amount of the formed pre-pit. This results in a problem of a poor utilization efficiency of a disk record surface.
Then, the present invention is proposed from the viewpoint of the above mentioned problems. It is therefore an object of the present invention to provide a method of and an apparatus for recording control information (i.e. pre-information) to an information record medium, a method of and an apparatus for recording record information to the information record medium to which the control information is recorded in advance, and the information record medium to which the control information is recorded in advance, which can improve a recording density of the record information and an accuracy in the reproduction of the record information.
The above object of the present invention can be achieved by a first method of recording, onto a guide track of an information record medium, control information to control at least one of recording and reproducing operations of record information on the information record medium. The first method is provided with the steps of: generating a control information timing signal one after another at an interval corresponding to a length of a control information unit equal to an N (N: predetermined integer not less than 2) multiple of a length of a record information unit of the record information; and recording the control information onto the guide track of the information record medium, on the basis of a timing corresponding to the control information timing signal.
According to the first method of the present invention, the control information timing signal is generated one after another at the interval corresponding to the length of the control information unit equal to the N multiple of the length of the record information unit. Then, the control information is recorded onto the guide track of the information record medium, on the basis of the timing corresponding to the control information timing signal. Thus, as compared with a case that the control information is recorded for all of the record information unit, the amount of the control information recorded on the whole information record medium can be reduced by the factor of 1/N, and that the recording density of the record information can be certainly improved. Further, it is possible to easily form a recording layer with a desirable thickness on the information record medium to which the control information has been recorded in advance.
In one aspect of the first method, the control information is pre-information including at least address information indicative of a record position on the information record medium of the record information, the record information unit is one synchronization frame, and in the generating step, the control information timing signal is generated by doubling said one synchronization frame.
According to this aspect of the first method, since the control information timing signal is generated by doubling said one synchronization frame, the pre-information is recorded once per two synchronization frames. Thus, as compared with a case that the pre-information is recorded for all of the synchronization frames, the amount of the pre-information recorded on the whole information record medium can be reduced by half, and that the recording density of the record information can be certainly improved. Further, it is possible to easily form a recording layer with a desirable thickness on the information record medium to which the pre-information has been recorded in advance.
In another aspect of the first method, the control information has a length along the guide track equal to an integer multiple of a unit length corresponding to a pit interval along the guide track defined by a recording format of the record information, for a record pit to be formed on the information record medium in correspondence with the record information in the recording operation, and in the recording step, the control information is recorded for each control information unit, by a control information pit having a length shorter along the guide track than the shortest pit length of the record pit.
According to this aspect of the first method, since the control information is recorded for each control information unit, by the control information pit having the length shorter than the shortest pit length of the record pit, the control information is recorded to have a pit length different from any pit length of the record information. Thus, it is possible to easily separate the record information and the control information from each other in the reproducing operation.
In another aspect of the first method, in the generating step, the control information timing signal is generated at such an interval that positions of the control information recorded on adjacent turns of the guide track are not on a straight line perpendicular to the guide track on the information record medium.
According to this aspect of the first method, since the control information timing signal is generated at such an interval that positions of the control information recorded on adjacent turns of the guide track are not on the straight line perpendicular to the guide track on the information record medium, it is possible to prevent the control information on the adjacent turns of the guide track from interfering or leaking to each other in the recording or reproducing operation.
In another aspect of the first method, the generating step is provided with the steps of: generating an even timing signal, as a first kind of the control information timing signal corresponding to an even numbered record information unit in a record information unit row comprising M (M: predetermined integer not less than 2) record information units; generating an odd timing signal, as a second kind of the control information timing signal corresponding to an odd numbered record information unit in the record information unit row; and selecting one of the even and odd timing signals such that positions of the control information recorded on adjacent turns of the guide track are not on a straight line perpendicular to the guide track on the information record medium. In the recording step, the control information is recorded onto the guide track of the information record medium, on the basis of a timing corresponding to the selected one of the even and odd timing signals.
According to this aspect of the first method, in the generating step, the even timing signal corresponding to the even numbered record information unit in the record information unit row is generated, while the odd timing signal corresponding to the odd numbered record information unit in the record information unit row is generated. At this time, one of the even and odd timing signals is selected such that positions of the control information recorded on adjacent turns of the guide track are not on the straight line perpendicular to the guide track on the information record medium. Then, in the recording step, the control information is recorded onto the guide track of the information record medium, on the basis of the timing corresponding to the selected one of the even and odd timing signals. Thus, since the control information is recorded only in the even or odd numbered record information unit, as compared with a case that the control information is recorded for all of the record information unit, the amount of the control information recorded on the whole information record medium can be reduced by about half, and that the recording density of the record information can be certainly improved. Further, it is possible to easily form a recording layer with a desirable thickness on the information record medium to which the control information has been recorded in advance. Furthermore, it is possible to prevent the control information on the adjacent turns of the guide track from interfering or leaking to each other in the recording or reproducing operation.
In this aspect of the first method, the selecting step may be preferably provided with the steps of: storing the selected one of the even and odd timing signals for one turn of the guide track; and selecting one of the even and odd timing signals for another turn of the guide track next to said one turn, on the basis of the stored one of the even and odd timing signals.
In this case, at first, the selected one of the even and odd timing signals is stored for one turn of the guide track. Later, one of the even and odd timing signals is newly selected for another turn of the guide track next to said one turn, on the basis of the stored one of the even and odd timing signals. Thus, it is possible, by use of a relatively simple construction, to select one of the even and odd timing signals such that positions of the control information recorded on adjacent turns of the guide track are not on the straight line perpendicular to the guide track on the information record medium.
The above object of the present invention can be also achieved by a first apparatus for recording, onto a guide track of an information record medium, control information to control at least one of recording and reproducing operations of record information on the information record medium. The first apparatus is provided with: a generating unit for generating a control information timing signal one after another at an interval corresponding to a length of a control information unit equal to an N (N: predetermined integer not less than 2) multiple of a length of a record information unit of the record information; and a recording unit for recording the control information onto the guide track of the information record medium, on the basis of a timing corresponding to the control information timing signal.
According to the first apparatus of the present invention, the control information timing signal is generated, by the generating unit, one after another at the interval corresponding to the length of the control information unit equal to the N multiple of the length of the record information unit. Then, the control information is recorded, by the recording unit, onto the guide track of the information record medium, on the basis of the timing corresponding to the control information timing signal. Thus, in the same manner as the above described first method of the present invention, the amount of the control information can be reduced, and that the recording density of the record information can be improved. Further, it is possible to easily form the recording layer with the desirable thickness.
In one aspect of the first apparatus, the control information is pre-information including at least address information indicative of a record position on the information record medium of the record information, the record information unit is one synchronization frame, and the generating unit generates the control information timing signal by doubling said one synchronization frame.
According to this aspect of the first apparatus, in the same manner as the first method of the present invention, the amount of the pre-information can be reduced, and that the recording density can be improved. Further, it is possible to easily form the recording layer with the desirable thickness.
In another aspect of the first apparatus, the control information has a length along the guide track equal to an integer multiple of a unit length corresponding to a pit interval along the guide track defined by a recording format of the record information, for a record pit to be formed on the information record medium in correspondence with the record information in the recording operation, and the recording unit records the control information for each control information unit, by a control information pit having a length shorter along the guide track than the shortest pit length of the record pit.
According to this aspect of the first apparatus, in the same manner as the first method of the present invention, it is possible to easily separate the record information and the control information from each other in the reproducing operation.
In another aspect of the first apparatus, the generating unit generates the control information timing signal at such an interval that positions of the control information recorded on adjacent turns of the guide track are not on a straight line perpendicular to the guide track on the information record medium.
According to this aspect of the first apparatus, in the same manner as the first method of the present invention, it is possible to prevent the control information on the adjacent turns of the guide track from interfering or leaking to each other in the recording or reproducing operation.
In another aspect of the first apparatus, the generating unit is provided with: a first generating device for generating an even timing signal, as a first kind of the control information timing signal corresponding to an even numbered record information unit in a record information unit row comprising M (M: predetermined integer not less than 2) record information units; a second generating device for generating an odd timing signal, as a second kind of the control information timing signal corresponding to an odd numbered record information unit in the record information unit row; and a selecting device for selecting one of the even and odd timing signals such that positions of the control information recorded on adjacent turns of the guide track are not on a straight line perpendicular to the guide track on the information record medium. The recording unit records the control information onto the guide track of the information record medium, on the basis of a timing corresponding to the selected one of the even and odd timing signals.
According to this aspect of the first apparatus, in the same manner as the first method of the present invention, the amount of the control information can be reduced by about half, and that the recording density can be certainly improved. Further, it is possible to easily form the recording layer with the desirable thickness. Furthermore, it is possible to prevent the control information on the adjacent turns of the guide track from interfering or leaking to each other in the recording or reproducing operation.
In this aspect of the first apparatus, the selecting device may be preferably provided with: a memory for storing the selected one of the even and odd timing signals for one turn of the guide track; and a selector for selecting one of the even and odd timing signals for another turn of the guide track next to said one turn, on the basis of the stored one of the even and odd timing signals.
In this case, in the same manner as the first method of the present invention, it is possible, by use of a relatively simple construction, to select one of the even and odd timing signals such that positions of the control information recorded on adjacent turns of the guide track are not on the straight line perpendicular to the guide track on the information record medium.
The above object of the present invention can be also achieved by an information record medium provided with: a substrate having an information record surface; an information record track formed on the information record surface in a spiral or coaxial shape, for recording record information; a guide track formed on the information record surface in parallel to the information record track, for guiding a light beam, which is to perform at least one of recording and reproducing operations of the record information, to the information record track; and a control information for controlling at least one of the recording and reproducing operations, recorded on the guide track at an interval corresponding to a length of a control information unit equal to an N (N: predetermined integer not less than 2) multiple of a length of a record information unit of the record information.
According to the information record medium of the present invention, as compared with an information record medium in which the control information is recorded for all of the record information unit, the amount of the control information recorded on the whole information record medium can be reduced by the factor of 1/N, and that the recording density of the record information can be certainly improved. Further, it is possible to easily form a recording layer with a desirable thickness on the information record medium to which the control information has been recorded in advance.
In one aspect of the information record medium, the control information is pre-information including at least address information indicative of a record position on the information record surface of the record information, the record information unit is one synchronization frame, and the pre-information is recorded on the guide track for each pre-information unit, which is obtained by doubling said one synchronization frame.
According to this aspect of the information record medium, as compared with an information record medium in which the pre-information is recorded for all of the synchronization frames, the amount of the pre-information recorded on the whole information record medium can be reduced by half, and that the recording density of the record information can be certainly improved. Further, it is possible to easily form a recording layer with a desirable thickness on the information record medium to which the pre-information has been recorded in advance.
In another aspect of the information record medium, the control information has a length along the guide track equal to an integer multiple of a unit length corresponding to a pit interval along the guide track defined by a recording format of the record information, for a record pit to be formed on the information record surface in correspondence with the record information in the recording operation, and the control information is recorded for each control information unit, by a control information pit having a length shorter along the guide track than the shortest pit length of the record pit.
According to this aspect of the information record medium, it is possible to easily separate the record information and the control information from each other in the reproducing operation.
In another aspect of the information record medium, positions of the control information recorded on adjacent turns of the guide track are not on a straight line perpendicular to the guide track on the information record surface.
According to this aspect of the information record medium, it is possible to prevent the control information on the adjacent turns of the guide track from interfering or leaking to each other in the recording or reproducing operation.
In another aspect of the information record medium, the information record medium is further provided with the record information, which is recorded on the information record track by a record pit formed in correspondence with the record information in the recording operation and which has a synchronization signal for achieving a synchronization in the reproducing operation, wherein the control information has a length along the guide track equal to an integer multiple of a unit length corresponding to a pit interval along the guide track defined by a recording format of the record information, the control information is recorded for each control information unit, by a control information pit having a length shorter along the guide track than the shortest pit length of the record pit, and positions of the control information and the synchronization signal recorded on adjacent turns of the guide track and the information record track are on a straight line perpendicular to the guide track on the information record surface.
According to this aspect of the information record medium, since the control information is recorded to have a pit length different from any pit length of the record information, it is possible to easily separate the record information and the control information from each other in the reproducing operation. Further, the positions of the control information and the synchronization signal recorded on adjacent turns of the guide track and the information record track are on the straight line perpendicular to the guide track, it is possible to easily obtain the timing relationship between the record information and the control information, and easily separate them from each other in the reproducing operation.
The above object of the present invention can be also achieved by a second method of recording record information onto the above described information record medium of the present invention. The second method is provided with the steps of: detecting the control information from the information record medium; generating the record information on the basis of a record signal inputted from the external such that a synchronization signal is added to each record information unit in correspondence with the detected control information; and recording the generated record information onto the information record track.
According to the second method of the present invention, in advance of actually recording the record information, the control information is firstly detected from the information record medium. Secondly, the record information is generated on the basis of a record signal inputted from the external such that the synchronization signal is added to each record information unit in correspondence with the detected control information. Finally, the generated record information is recorded onto the information record track. Thus, on the information record medium which has been recorded by the second method, the position of the synchronization signal on the information record track and the position of the control information on the guide track are adjacent to each other, so that it is possible to easily separate the record information and the control information from each other in the detection of the control signal and the reproduction of the record information.
The above object of the present invention can be also achieved by a second apparatus for recording record information onto the above described information record medium of the present invention. The second apparatus is provided with: a detecting unit for detecting the control information from the information record medium; a record information generating unit for generating the record information on the basis of a record signal inputted from the external such that a synchronization signal is added to each record information unit in correspondence with the detected control information; and a recording unit for recording the generated record information onto the information record track.
According to the second apparatus of the present invention, in advance of actually recording the record information, the control information is firstly detected, by the detecting unit, from the information record medium. Secondly, the record information is generated, by the record information generating unit, on the basis of a record signal inputted from the external such that the synchronization signal is added to each record information unit in correspondence with the detected control information. Finally, the generated record information is recorded, by the recording unit, onto the information record track. Thus, in the same manner as the second method of the present invention, it is possible to easily separate the record information and the control information from each other in the detection of the control signal and the reproduction of the record information.
As described above, according to the present invention, it is possible to prevent a direct current (DC) element from being changed in the detected or reproduced signal of the information record medium, and also possible to protect the jitter due to the unstableness of the pit shape from being generated in the detected or reproduced signal, so that the detection of the control information and the reproduction of the record information can be accurately performed while the recording density of the record information can be certainly improved.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to a preferred embodiment of the invention when read in conjunction with the accompanying drawings briefly described below.